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When a piece of charcoal enclosed in a cylinder containing air is ignited

When a piece of charcoal enclosed in a cylinder containing air is ignited
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
  • A The toatl volume of air is increased
  • B The relative amount of oxygen present is increased
  • C The relative amount of nitrogen present is decreased
  • D The relative amount of carbondioxide present is increased
  • E The ratio of oxygen to nitrogen in the system is increased
Correct Answer: Option D
Explanation:
The correct answer is D. The relative amount of carbon dioxide present is increased


- Charcoal is mostly carbon (C).
- When ignited in air (which is mostly nitrogen and oxygen), the carbon reacts with oxygen in the air to form carbon dioxide (COâ‚‚):

\[
C + Oâ‚‚ \rightarrow COâ‚‚
\]

- This reduces the oxygen content and increases the carbon dioxide content in the air inside the cylinder.
- The nitrogen remains largely unchanged because it is inert under these conditions.


Key Observations:
- Oxygen decreases.
- Carbon dioxide increases.
- Nitrogen stays the same.
- The total volume of gas may change slightly due to temperature, but composition change is more relevant here.

Correct conclusion: The relative amount of carbon dioxide increases → Answer: D.

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